Using Only Link-Local Addressing inside an IPv6 Network
RFC 7404
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Type |
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RFC - Informational
(November 2014; Errata)
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Last updated |
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2015-10-14
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IETF
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plain text
pdf
html
bibtex
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Reviews |
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WG state
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Submitted to IESG for Publication
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Document shepherd |
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Gunter Van de Velde
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Shepherd write-up |
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Show
(last changed 2014-03-13)
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IESG state |
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RFC 7404 (Informational)
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Consensus Boilerplate |
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Yes
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Telechat date |
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Responsible AD |
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Joel Jaeggli
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Send notices to |
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(None)
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IANA review state |
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Version Changed - Review Needed
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No IC
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Internet Engineering Task Force (IETF) M. Behringer
Request for Comments: 7404 E. Vyncke
Category: Informational Cisco
ISSN: 2070-1721 November 2014
Using Only Link-Local Addressing inside an IPv6 Network
Abstract
In an IPv6 network, it is possible to use only link-local addresses
on infrastructure links between routers. This document discusses the
advantages and disadvantages of this approach to facilitate the
decision process for a given network.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7404.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Behringer & Vyncke Informational [Page 1]
RFC 7404 Link-Local Only November 2014
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Using Link-Local Addressing on Infrastructure Links . . . . . 2
2.1. The Approach . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Advantages . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Caveats . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4. Internet Exchange Points . . . . . . . . . . . . . . . . 6
2.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Security Considerations . . . . . . . . . . . . . . . . . . . 8
4. Informative References . . . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
An infrastructure link between a set of routers typically does not
require global or unique local addresses [RFC4193]. Using only link-
local addressing on such links has a number of advantages; for
example, routing tables do not need to carry link addressing and can
therefore be significantly smaller. This helps to decrease failover
times in certain routing convergence events. An interface of a
router is also not reachable beyond the link boundaries, therefore
reducing the attack surface.
This document discusses the advantages and caveats of this approach.
Note that some traditional techniques used to operate a network, such
as pinging interfaces or seeing interface information in a
traceroute, do not work with this approach. Details are discussed
below.
During WG and IETF last call, the technical correctness of the
document was reviewed; however, debate exists as to whether to
recommend this technique. The deployment of this technique is
appropriate where it is found to be necessary.
2. Using Link-Local Addressing on Infrastructure Links
This document discusses the approach of using only link-local
addresses (LLAs) on all router interfaces on infrastructure links.
Routers don't typically need to receive packets from hosts or nodes
outside the network. For a network operator, there may be reasons to
use addresses that are greater than link-local scope on
infrastructure interfaces for certain operational tasks, such as
pings to an interface or traceroutes across the network. This
document discusses such cases and proposes alternative procedures.
Behringer & Vyncke Informational [Page 2]
RFC 7404 Link-Local Only November 2014
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